Coupling devices are known for transferring fluids from a storage tank into a mobile tank or other container such as found on an automobile, bus, truck, aircraft, etc. For certain fluids, for example, cryogenic fluids (e.g., liquid nitrogen, liquid argon, liquid oxygen), the coupling must be robust and able to withstand particularly difficult fueling environments (e.g., it must prevent coupling freeze-up). It is also important that the coupling prevent spills and have dimensions which minimize the clearance necessary for coupling the nozzle to the receptacle. It is further important that the coupling have ease of operation for various skill levels of operators, and be ergonomically friendly.
Certain nozzles and receptacles are known which substantially satisfy these demands and provide easy coupling and uncoupling of the nozzle from the receptacle. For example, a series of coupling devices available from the assignee of the present invention for liquid natural gas (LNG) applications include a valved nozzle and valved receptacle which are releasably interconnected by a locking collar, and have interface sealing surfaces to prevent fluid leakage. The nozzle interface sealing surface is arranged on a carrier that is axially slideable relative to the nozzle housing. The carrier also provides a valve seat for the nozzle valve. An actuator lever on the nozzle moves both the nozzle valve poppet toward and away from the nozzle valve seat as well as the nozzle interface sealing surface toward and away from the receptacle interface sealing surface. The interface sealing surfaces are brought together before the receptacle and nozzles valves are opened during connect, and are maintained together until after the valves are closed for disconnect. Any fluid trapped between the closed valves and the interface sealing surfaces is vented before disconnect as the actuator lever is moved to a disconnect position.
In such prior coupling, the receptacle includes an annular flange with radially-outward projecting lugs which are received in appropriately-spaced slots in the locking collar at the front end of the nozzle. When the locking collar is rotated, the lugs are engaged by the locking collar to retain the nozzle on the receptacle. It is also known to provide helical slots along the nozzle, which receive radially-outward projecting pins on the receptacle. Rotation of the locking collar on the nozzle (or of the nozzle itself in some designs) pulls the nozzle toward the receptacle for secure attachment. The open end of the nozzle internally receives the end of the receptacle.
Such a coupling device has received widespread acceptance in the marketplace. Nevertheless, the above described coupling device has a number of components which are fairly complicated, and require significant time and effort to manufacture and assemble, as well as to rebuild during normal repair and maintenance. The components are also fairly complicated to manufacture and assemble. In addition, while the interface seals of this coupling device are field-serviceable, it is believed there is a demand for improved interface seal design which is more reliable and does not require as frequent servicing and maintenance. It is therefore believed there is a demand in the industry for a further improved coupling device, particularly for fluids such as cryogenic fluids, which overcomes at least some of these drawbacks, and which retains many of the features and advantages of assignee's prior coupling designs. In addition, it is also believed there is a demand for different coupling structures to securely couple the nozzle to the receptacle, and which allow venting of the coupling before full disconnect.